Generalize the LinkCache clear() call to JobRunner

The use for this logic is not specific to RefreshLinksJob

Change-Id: I4bb911ab5882d1795e12163df8ae6b227c58bc8a

includes/jobqueue/JobRunner.php

@@ -191,7 +191,10 @@ class JobRunner implements LoggerAwareInterface {
 				}
 				// Commit all outstanding connections that are in a transaction
 				// to get a fresh repeatable read snapshot on every connection.
+				// Note that jobs are still responsible for handling slave lag.
 				wfGetLBFactory()->commitAll();
+				// Clear out title cache data from prior snapshots
+				LinkCache::singleton()->clear();
 				$timeMs = intval( ( microtime( true ) - $jobStartTime ) * 1000 );
 				$timeMsTotal += $timeMs;
 

includes/jobqueue/jobs/RefreshLinksJob.php

@@ -139,10 +139,6 @@ class RefreshLinksJob extends Job {
 			wfGetLB()->waitFor( $this->params['masterPos'] );
 		}
 
-		// Clear out title cache data from prior job transaction snapshots
-		$linkCache = LinkCache::singleton();
-		$linkCache->clear();
-
 		// Fetch the current page and revision...
 		$page = WikiPage::factory( $title );
 		$revision = Revision::newFromTitle( $title, false, Revision::READ_NORMAL );